tool change repetier

Hi,
After few days of recherche I need some help.
I would like the printer applies a different tool change gcode when it passes from the head 1 to the head 2 and from the head 2 to the head 1. I tried to do different configuration in slic3r for the head 1 and head 2 and then select them in extruder 1 and extruder 2 in repetier, but the printer only applies the configuration put in "printer setting". So it applies the same tool change gcode every time.
I thing it's possible, it would be a pity that it is not...